[Droplet exposure during tracheotomy : Case analysis and consequences with respect to COVID-19 patients]. / Tröpfchenexposition bei Tracheotomie : Fallanalyse und Konsequenzen in Bezug auf COVID-19-Patienten.

BACKGROUND: The COVID(coronavirus disease)-19 pandemic is characterized by high infectivity, droplet transmission, and high viral load in the upper respiratory tract. Severe disease courses are associated with interstitial pneumonia and ventilated patients, in whom tracheotomy (TT)-a droplet- and aerosol-producing medical intervention-is regularly necessary. TT as a potential infection risk for medical staff is scarcely found in the literature. Therefore, the aim of this study was to quantify droplet exposure of the surgical team during TT, to better define the requirements for personal protective equipment (PPE). MATERIALS AND METHODS: Surgical TT was performed in four non-infectious patients, during which the surgeon and his assistant both wore a surgical nasal mask with a transparent visor. After the procedure, the type, distribution, and number of droplets on the visor were determined macroscopically and microscopically. RESULTS: An average of 29 droplets were found on the middle third of the visor, 4 on the right third, and 13 on the left third, with an average droplet size of 571 µm (±â€¯381 µm). The smallest droplets were 55 µm, the largest 1431 µm. An increase in the number of droplets was found with increased ventilation during the procedure. Blood droplets were more common than secretion droplets. CONCLUSION: Contamination of the visor with droplets was demonstrated. Especially in the case of TT in highly infectious patients, e.g., COVID-19 patients, the use of hooded headgear in combination with breathing apparatus with air purification and power supply is recommended to ensure best protection from infection for the surgeon and the surgical assistant.

[Visualisation and Radiofrequency Ablation of Sympathetic Innervation Loci in the Left Atrium in Patients with Paroxysmal Atrial Fibrillation].

INTRODUCTION: A novel cardiac gamma camera utilizes the radiopharmaceutical Iodine-123-Meta-iodobenzylguanidine (123I-MIBG) to visualize cardiac sympathetic innervation. Physiological accumulation of 123I-mIBG provides an anatomical quantitative determination of the structures of the autonomic nervous system (ANS) with discrete uptake areas (DUA) of sympathetic activity located in the left atrium (LA) corresponding to the main ganglionic plexi (GP) clusters that could not previously be visualized. AIM: to visualize the DUA of the heart in patients with paroxysmal atrial fibrillation (AF) and to assess the effect of radiofrequency ablation (RFA) on DUA in LA. MATERIALS AND METHODS: Computed tomography (CT) of the heart and radionuclide imaging with 123I-mIBG were performed in 15 patients with paroxysmal AF. The results of the study were combined with preliminary taken CT images to create a detailed anatomical map of the sympathetic activity of the heart. The processed images were combined with the 3D reconstruction of the LA, obtained with the navigation system (CARTO 3, CARTO RMT). In DUA, high-frequency stimulation (HFS) followed by RF ablation was performed using the current recommended parameters. RESULTS: Forty-eight DUA (median 3 [3; 3]) were identified. Average activity of DUA was 1315 [1171; 1462] cnt / sec / ml. Positive response to HFS in the DUA was obtained in 8 (53.3 %) patients. Prior to ablation, no response was received to HFS in areas of LA outside the DUA. After ablation, there was no response to HFS in the DUA sites. At repeated scans 3 DUA (median 0 [0; 0]; p<0.001 compared with preoperative data) were observed. Activity of DUA significantly decreased to 819 [684; 955] cnt / sec / ml (p<0.001 as compared with preoperative data). Thirteen of 13 of 15 patients (87 %) had no AF / AT / AFL recurrences for 6 month follow up. CONCLUSION: In patients with AF, the areas of sympathetic activity in LA can be visualized by physiological localized uptake of 123I-mIBG. Radiofrequency catheter ablation can target the identified sympathetic innervation structures in AF patients precisely and effectively.

Influence of patient-specific anatomy on medical computed tomography and risk evaluation of minimally invasive surgery at the otobasis.

PURPOSE: With the increasing use of new minimally invasive approaches in temporal bone surgery, the need arises for evaluation of the risk of injury to sensitive anatomical structures. The factors that influence the measurement uncertainty (variation in representation of position and shape of anatomical structures) of imaging are of relevance. We investigate the effect of patients' anatomy on the measurement uncertainty of medical CT. METHODS: Six formalin-fixed temporal bones were used, fiducial markers were bone-implanted, and 20 CT scans of each temporal bone were generated. Surgically threatened anatomical structures of importance were defined. Manual segmentation was performed to create 3D surface models, and different Gaussian filters were applied. Analysis points were established along the border of the superior semicircular canal to determine the deviation between the 3D images of the labyrinth. The standard uncertainty was calculated, and one-way analysis of variance was performed (significance level = 5%) to evaluate the effect of certain factors (patient, side, Gaussian filter) on the measurement uncertainty. RESULTS: The influence of patient-specific anatomy on the measurement uncertainty of medical CT (p = 0.049) was demonstrated for the first time. The applied Gaussian filter (p = 0.622) and the patient's side (p = 0.341) showed no significant effect. CONCLUSION: The applied method and the results of the statistical analysis suggest that the patient's individual anatomical conditions affect the measurement uncertainty of medical CT. Thus, the patient's anatomy must be considered as an important influencing factor during risk evaluation concerning minimally invasive and image-guided surgery.

[Complications of anterior skull base surgery]. / Komplikationen bei Operationen an der Rhinobasis.

Anterior skull base operations are complex surgical procedures that are performed to treat serious and complicated diseases. Despite significant advances in surgical techniques, complications are relatively frequent and can be serious. Endoscopic skull base surgery seems to be associated with less complications than open techniques. Different classifications aimed at categorizing these complications have been suggested, the use of which can be recommended when reporting complication rates. The most relevant and frequent complications of anterior skull base surgery are hemorrhage, cerebrospinal fluid (CSF) leak, meningitis, and cranial nerve injury. Careful planning, close interdisciplinary cooperation, the competence of the skull base center and its members, and rigorous quality management are decisive for the avoidance of complications. With respect to the frequency and the seriousness of the complications, their meticulous and complete discussion with the patient before obtaining informed consent plays a central role.

[Surgical simulation on the lateral skull base]. / Chirurgische Simulation an der Laterobasis.

Critical neurovascular structures are confined in a small bony space at the lateral skull base. Thus, high quality of surgical training and planning of minimally invasive procedures is crucial. Simulation of lateral skull base procedures can improve motor skills, anatomical orientation, and complication management in a safe environment. Thus, simulation training can be beneficial for skull base surgeons. Minimally invasive interventions at the lateral skull base are under research, and several authors have presented approaches through single or multiple drilled ports. Precise planning and simulation of such interventions is essential because even submillimeter errors can lead to damage to critical anatomical structures. Therefore, high demands have been set for the accuracy of computer-assisted surgery.

[Physical Properties of Squamous Cell Carcinoma Cells using Atomic Force Microscopy]. / Bestimmung elastischer Eigenschaften von Plattenepithelkarzinomzellen mittels Rasterkraftmikroskopie.

INTRODUCTION: Malignant and benign cells differ according to their elasticity. An atomic force microscope is a useful tool for measuring these mechanical cell properties. If cells of different dignity show different resonance behavior, due to their different elasticity, a selective ablation of specific tissue types by ultrasound would be possible. The goal is a highly selective ablation of tumor tissue without damaging healthy tissue. MATERIALS AND METHODS: We performed elasticity measurements of tumor cells (UD-01 cell line) with an atomic force microscope. In a further step, an ultrasound applicator has been positioned and the morphological changes of the cells during the treatment were documented. RESULTS: Different elasticities on the squamous cells were measured, depending on the location. Below a defined maximum amplitude the morphological cell changes were caused solely by ultrasonic excitation. SUMMARY: The atomic force microscope is suitable for the determination of the individual cell elasticity. The data collected could be the basis for treatment modalities that lead to a very selective damage for malignant cells.

Nasal levels of soluble IL-33R ST2 and IL-16 in allergic rhinitis: inverse correlation trends with disease severity.

BACKGROUND: Serum levels of IL-16, IL-33 and the decoy receptor of IL-33, soluble ST2, are elevated in allergic rhinitis. Recent studies show that IL-16, soluble ST2 or anti-IL-33 reduce type 2 cytokines (such as IL-5) and eosinophilia in murine models of allergic asthma or allergic rhinitis respectively. OBJECTIVE: In this study, we studied the release of IL-5, IL-16, IL-33 and soluble ST2 in allergic rhinitis patients after nasal allergen challenge and natural pollen exposure. METHODS: The nasal lavages of 15 allergic and 14 non-allergic volunteers were collected during the pollen allergy season. In addition, six allergic volunteers underwent unilateral nasal allergen and control challenge out of season and nasal secretions and sera were collected. IL-5, IL-16, IL-33 and soluble ST2 in nasal secretions and sera were measured by electrochemiluminescent assay or ELISA, respectively. RESULTS: Nasal IL-5, IL-16 and soluble ST2 levels were significantly increased in seasonally pollen exposed allergic volunteers compared to control subjects (P < 0.001, P = 0.018 and P = 0.002 respectively), whereas IL-33 remained undetectable. Nasal IL-16 showed a weak inverse correlation trend with nasal symptoms (r = -0.48, P = 0.07). Nasal soluble ST2 concentrations were inversely correlated with nasal symptoms (r = -0.61, P = 0.02) and positively correlated with IL-16 (r = 0.56, P = 0.03). Significant increases of nasal IL-5, IL-16 and ST2 but not IL-33 were observed after nasal allergen challenge. At 24 h after allergen challenge, local ST2 and IL-5 concentrations showed an inverse correlation trend (r = -0.83, P = 0.04). Serum levels of IL-5, IL-16 and soluble ST2 rose in at least five of six volunteers tested at 5 or 24 h post-challenge. CONCLUSIONS AND CLINICAL RELEVANCE: The observed upregulation of soluble ST2 and IL-16 after nasal allergen challenge and during peak pollination season suggests potential regulatory roles of these cytokines in the inflammatory reaction in allergic rhinitis.